1. Field
The present invention relates to devices and methods for injection of media into human and animal tissue, in particular into hard tissue.
2. Description of Prior Art
U.S. Pat. No. 4,787,893 discloses a hand-grip element for injection of liquid substances, in particular anesthetics, in which rotation of a receptacle sleeve is induced by a drive motor. The ampoule with the substance to be injected can be inserted into the receptacle sleeve, so that the rotational movement is transferred to the ampoule and the injection needle connected to it. The hand-grip element is thus used not only for injection but also for penetrating into or through tissue, i.e., bones, for example, in particular the jawbone, into which the substance is to be injected.
The connection of the ampoule to the injection needle is accomplished by puncturing a rubber stopper, the so-called septum, which is provided at one end of the ampoule, so that the injection needle protrudes into the ampoule reservoir with the injection liquid. However, this connection has proven to be a disadvantage because in drilling through the bone, the needle, which serves as the drill, is decelerated but the holding power of the rubber stopper for the needle is too low to transfer the decelerating effect to the ampoule as well, which thus results in a relative movement between the needle and the ampoule. Abrasion occurs on the rubber stopper due to this relative movement, i.e., due to the rubber stopper rotating more rapidly and the decelerated injection needle rotating more slowly. At least some of the abrasion enters the injection liquid in the form of fine rubber particles, so there is the risk that these particles may be injected into the tissue with the injection liquid. More of the abrasion enters the hand-grip element, where it can lead to negative effects or damage to components.
Therefore, the object of the present invention is to design a hand-grip element so that no abrasion occurs.